It has always been my understanding that correct support of the diaphragmatic region is a direct result of right breathing. In my experience I've noticed that most instruction has been about manipulating this region of the body in attempts to control the flow of air, unaware that the vocal cords are responsible for controlling the flow and compression. The vocal folds, and proper placement in the mask, have just as much to do with support of the singing mechanism as the diaphragm.
Through extensive study and research over the last 15 years, I have discovered a little-known secret. Proper use of the diaphragm is an automatic result of having learned how to inhale the air correctly.
In my latest book, Vocal Strength and Power published and released by Hal Leonard Corp., I have included a glossary of the most commonly used words by instructors to describe how to employ and gain support with this region of the body. Frankly, when looking up some of these words, I was quite surprised myself by the true meanings. This forced me to change my own vernacular when instructing after realizing that all the faulty perception with regard to how to engage this region of the body properly came down to the true meaning of words.
In my first two books, I purposely stayed away from instruction on the diaphragm and focused on how to get the other two support mechanisms (the cords and the mask) to work together. At the time, I still did not have the words to describe how to engage the diaphragm correctly. I only knew what was wrong: Singers were squeezing the neck and belly muscles, pushing up the belly muscles, and putting strain on the neck muscles.
Squeezing of any kind only results in feeling like you must force and blow the air out for sound. This habit not only feels unnatural and strained, but after a few years of singing this way, many singers find themselves in doctor's offices trying to uncover the reasons why they are no longer able to sing like they once did. Unfortunately, some will require rehabilitation and in other cases, surgery.
About the Inhale
Air is already in the lungs and body from natural breathing and inhales. Because of this truth, it is a misconception that more is needed for singing. In fact, if you take in too much, the vocal folds will be unable to control the flow for sound and compression.
There is an art to inhalation. Taking in heaps of air can be not only be damaging, but it also brings on fatigue. See for yourself. Take in as much air as you can and then exhale it. Repeat this action over and over again for about five minutes and you're bound to feel a little tired if you don't faint from hyperventilation in the meantime! Now imagine breathing heavily and hard like this, but with sound, over and over again between words and phrases of songs. A tired singer's instinct will say, I need to take in more air in order to keep that power going, hit those higher notes, and sustain the note (or notes) if needed. Not so. This is literally exhausting, especially on a gig. The more air you keep losing, your head will keep telling you to take more and more in. This will set you up for a no win cycle.
Important to remember but not so easy to employ is the idea that the vocal folds do not need much air to produce a strong tone, or to prolong one. In my latest book I have created exercises to re-train how to take the air in properly through use of the staccato.
This staccato is a bit different than most. It requires that you take tiny puffs of air between each note of the exercise. However, a tiny bit does not mean to hold the breath in any way. Nor does it mean to blow it all out on every phonated pitch. It's tricky but once learned, all three-support mechanisms will work as they should: naturally and automatically. You will not have to manipulate by tensing the muscles of any region of your body to achieve what you have wrongly perceived as support of the diaphragm.
Natural and Automatic
Going from one way of breathing to another is difficult; it takes the ability to focus one's efforts on re-training and requires repetitive practice of exactly how much air should be taken in for each phonation.
For engaging natural support upon inhalation during a staccato run, the belly (below the navel) will automatically become firm. It should stay nearly unmoving until after you have finished the last tone of a run. You should not have to strain it for this region to remain firm. If you strain to hold the belly out, you'll be holding the breath.
Because it is internal, it's hard to feel the movement of the diaphragm itself. The only part of your body you should feel moving is the upper abdomen (above the navel) jumping out and in as it is indirectly compressed by the moving diaphragm inside your rib cage. You can place your finger just below your breastbone to feel this movement.
On an inhalation, the diaphragm will automatically move down a bit. As it goes down, it pushes the upper abdomen out. On exhale the diaphragm and upper abdominal muscles very slowly return to their starting positions. (There is no need to blow out the air for this. You only need to relax your belly and leftover air is automatically expelled. Try it. Take in a breath and then just relax the belly. You should feel the air having left by itself). Only when the diaphragm relaxes completely do the upper abdominal muscles move back into their normal position. Squeezing the lower belly muscles at this point only fights the diaphragm's natural action).
Through the use of the new exercises I created to re-train the inhale/exhale action, the movement is much faster because the point of the repetitive exercises is to do everything in rapid succession. This will help to get the air and sound producing as if it is one continuous action, and working like a single unit.
Books: Vocal Strength and Power, published by Hal Leoanrd Corp, 2009
Advanced Vocal Technique: Middle Voice, Placement and Styles, published by Hal Leonard Corp, 2008
Vocal Technique: FInding Your Real Voice published by Hal Leonartd Corp 2002